diff --git a/dune/elasticity/materials/mooneyrivlindensity.hh b/dune/elasticity/materials/mooneyrivlindensity.hh index 2b4c35d697de4a44f8e37f6f9ededbcf28585954..37ba2729ca0698bd1f8d7f890160f89669679aeb 100644 --- a/dune/elasticity/materials/mooneyrivlindensity.hh +++ b/dune/elasticity/materials/mooneyrivlindensity.hh @@ -64,13 +64,14 @@ public: /* The Mooney-Rivlin-Density is given as a function of the eigenvalues of the right Cauchy-Green-Deformation tensor C = F^TF or the right Cauchy-Green-Deformation tensor B = FF^T. C = F^TF and B = FF^T have the same eigenvalues - we can use either one of them. - + There are three Mooney-Rivlin-Variants: ciarlet: W(F) = mooneyrivlin_a*(normF)^2 + mooneyrivlin_b*(normFinv)^2*detF^2 + mooneyrivlin_c*(detF)^2 - - ((dim-1)*mooneyrivlin_a + mooneyrivlin_b + 2*mooneyrivlin_c)*ln(detF) + (2*mooneyrivlin_a + 4*mooneyrivlin_b + 2*mooneyrivlin_c)*ln(detF), + where the last term is chosen s.t. W( t*I ) is minimal for t=1 log: W(F) = \sum_{i,j=0}^{i+j<=n} mooneyrivlin_ij * (I1 - 3)^i * (I2 - 3)^j + mooneyrivlin_k * ln(det(F))^2 square: W(F) = \sum_{i,j=0}^{i+j<=n} mooneyrivlin_ij * (I1 - 3)^i * (I2 - 3)^j + mooneyrivlin_k * 0.5 * (det(F) - 1)^2 - + For log and square: I1 and I2 are the first two invariants of C (or B), multiplied with a factor depending on det(F): I1 = (det(F)^(-2/dim)) * [ first invariant of C ] = (det(F)^(-2/dim)) * (sum of all eigenvalues of C) @@ -99,7 +100,8 @@ public: gradientInverse.invert(); field_type frobeinusNormFInverseSquared = gradientInverse.frobenius_norm2(); using std::log; - return mooneyrivlin_a*frobeniusNormFsquared + mooneyrivlin_b*frobeinusNormFInverseSquared*detF*detF + mooneyrivlin_c*detF*detF - ((dim-1)*mooneyrivlin_a + mooneyrivlin_b + 2*mooneyrivlin_c)*log(detF); + return mooneyrivlin_a*frobeniusNormFsquared + mooneyrivlin_b*frobeinusNormFInverseSquared*detF*detF + mooneyrivlin_c*detF*detF + - (2.0*mooneyrivlin_a + 4.0*mooneyrivlin_b + 2.0*mooneyrivlin_c)*log(detF); } else { diff --git a/test/mooneyrivlintest.cc b/test/mooneyrivlintest.cc index 8af6cbafcc51f0250a3249f3c5da96aa2a90fb94..330aedf378ee8cd6d8d338cf424a6c8df241669e 100644 --- a/test/mooneyrivlintest.cc +++ b/test/mooneyrivlintest.cc @@ -167,10 +167,10 @@ int main (int argc, char *argv[]) parameters["mooneyrivlin_a"] = "2.42e+6"; parameters["mooneyrivlin_b"] = "6.52e+6"; parameters["mooneyrivlin_c"] = "-7.34e+6"; - expectedEnergy = 68753239.6; - expectedGradientTwoNorm = 31244643.1; - expectedGradientInfinityNorm = 9673572.39; - expectedMatrixFrobeniusNorm = 1.67660965e+09; + expectedEnergy = 76302830.4; + expectedGradientTwoNorm = 40670527.3; + expectedGradientInfinityNorm = 11116511.8; + expectedMatrixFrobeniusNorm = 2.1978108e+09; int testCiarlet = assembleAndCompare(basis, parameters, x, expectedEnergy, expectedGradientTwoNorm, expectedGradientInfinityNorm, expectedMatrixFrobeniusNorm); return testCiarlet + testLog + testSquare;